Recreate an XML based on its values in Java

Question

I have an dynamic XML that needs to be transformed based on the values of its XML. The group nodes with an attribute type="newNode" needs to be removed because they are already derived.

I tried the following:

1. Create new nodes based on the XML and delete the unnecessary nodes but I encountered an issue when using doc.removeChild(node) saying

   Exception in thread "main" org.w3c.dom.DOMException: NOT_FOUND_ERR: An attempt is made to reference a node in a context where it does not exist.

   NodeList nodeList = doc.getElementsByTagName(NODE_MAPPINGS_NODE);
   for (int i = 0; i < nodeList.getLength(); i++) {
       Node nodeToBeRemoved = nodeList.item(i);
       if (nodeToBeRemoved.getNodeType() == Node.ELEMENT_NODE) {
           doc.getDocumentElement().removeChild(nodeToBeRemoved);
       }
   }
   

2. Created a new document based on the original document but I encountered an error saying

   Exception in thread "main" org.w3c.dom.DOMException: HIERARCHY_REQUEST_ERR: An attempt was made to insert a node where it is not permitted.

   NodeList nodeList = doc.getElementsByTagName(NODE_MAPPINGS_NODE);
   for (int i = 0; i < nodeList.getLength(); i++) {
       Node node = nodeList.item(i);
       if (node.getNodeType() == Node.ELEMENT_NODE) {
           if(!node.hasAttributes()) {
               Element elem = newDoc.createElement(node.getNodeName());
               newDoc.appendChild(elem);
           }
       }
   }
   

Here is the sample XML that I am trying to parse:

<root>
    <input>
        <nodeMappings type="newNode">
            <name>declarationType</name>
            <type>derived</type>
            <derivedValue>X</derivedValue>
        </nodeMappings>
        <nodeMappings type="newNode">
            <name>identificationNumber</name>
            <type>derived</type>
            <derivedValue>5000000612</derivedValue>
        </nodeMappings>
        <characteristicsOfTaxPayer>
            <nodeMappings type="newNode">
                <name>collectivePerson</name>
                <type>derived</type>
                <derivedValue>X</derivedValue>
            </nodeMappings>
        </characteristicsOfTaxPayer>
        <listTest>
            <nodeMappings type="newNode">
                <name>primaryKey</name>
                <type>derived</type>
                <derivedValue>1</derivedValue>
            </nodeMappings>
            <nodeMappings type="newNode">
                <name>value</name>
                <type>derived</type>
                <derivedValue>test1</derivedValue>
            </nodeMappings>
        </listTest>
        <listTest>
            <nodeMappings type="newNode">
                <name>primaryKey</name>
                <type>derived</type>
                <derivedValue>2</derivedValue>
            </nodeMappings>
            <nodeMappings type="newNode">
                <name>value</name>
                <type>derived</type>
                <derivedValue>test2</derivedValue>
            </nodeMappings>
        </listTest>
    </input>
</root>

After processing it should look like this:

<root>
    <input>
        <declarationType>X</declarationType>
        <identificationNumber>5000000612</identificationNumber>
        <characteristicsOfTaxPayer>
            <collectivePerson>X</collectivePerson>
        </characteristicsOfTaxPayer>
        <listTest>
            <primaryKey>1</primaryKey>
            <primaryKey>test1</primaryKey>
        </listTest>
        <listTest>
            <primaryKey>2</primaryKey>
            <primaryKey>test2</primaryKey>
        </listTest>
    </input>
</root>

Is there a better way to do this?

Answer 1

The complete job could be done with a simple xslt.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
  
  <xsl:output method="xml" encoding="utf-8" indent="yes"/>
  
  <!-- Identity template : copy all text nodes, elements and attributes -->   
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
  </xsl:template>
  
  <xsl:template match="nodeMappings[@type='newNode']" >
    <xsl:element name="{name/text()}"><xsl:value-of select="derivedValue/text()"/></xsl:element>
  </xsl:template>

</xsl:stylesheet>

If it's correct that there is one exception in convention: that the text-value name-element becomes the new created element, that is <name>value</name> becomes <primaryKey/> the xslt would be:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
  
  <xsl:output method="xml" encoding="utf-8" indent="yes"/>
  
  <!-- Identity template : copy all text nodes, elements and attributes -->   
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
  </xsl:template>
  
  <xsl:template match="nodeMappings[@type='newNode']" >
    <xsl:element name="{name/text()}"><xsl:value-of select="derivedValue/text()"/></xsl:element>
  </xsl:template>

  <xsl:template match="nodeMappings[@type='newNode'][name='value']" >
    <primaryKey><xsl:value-of select="derivedValue/text()"/></primaryKey>
  </xsl:template>

</xsl:stylesheet>